#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<string.h>
#include<sys/socket.h>
#include<arpa/inet.h>
#include<netinet/in.h>
#include<sys/types.h>
#include<netdb.h>

#define PORT 7838

int main(int argc,char* argv[])
{
        int sockfd;
        struct sockaddr_in their_addr;
        struct in_addr addr;
        struct hostent *he;
        int broadcast = 1;
        int num = 0;


        if(argc != 3)
        {
                fprintf(stderr,"Usage: broadcase hostname message\n");
                exit(1);
        }

        if( inet_aton(argv[1],&addr) == 0)
        {
                he = gethostbyname(argv[1]); //Domain
                addr.s_addr = (*(unsigned int *)*he->h_addr_list[0]);
        }

        if( (sockfd = socket(AF_INET,SOCK_DGRAM,0)) == -1 )
        {
                perror("socket function!\n");
                exit(1);
        }

        if( setsockopt(sockfd,SOL_SOCKET,SO_BROADCAST,&broadcast,sizeof(broadcast)) == -1)
        {
                perror("setsockopt function!\n");
                exit(1);
        }

        their_addr.sin_family = AF_INET;
        their_addr.sin_port = htons(PORT);
        their_addr.sin_addr = addr;

        if( (num = sendto( sockfd,argv[2],strlen(argv[2]),0,(struct sockaddr *)&their_addr,sizeof(struct sockaddr) )) == -1)
        {
                perror("sendto function!\n");
                exit(1);
        }

        printf("Send %d bytes to %s\n",num,inet_ntoa(their_addr.sin_addr) );

        close(sockfd);

        return 0;
}
